Cheap plastic trash, for several hundred bucks, it's really annoying nickle and diming by Triumph. They cheap out on some stuff that annoys me a lot. Handlebar controls are cheap and butt ugly, for instance. The rear wheel on the R3T too, mine looks atrocious now due to crappy quality coating, corroded and pitted. I may wind up having to get them chromed or something similar to the tune of $6-700 for the pair plus taxes and shipping and customs and lord knows what else, but that's for next winter...
My grips have held together but I haven't needed the heat that much. Yet. But I still carry the non-heated original in the pannier...
It's crazy that they aren't metal or at least have metal inserts to keep stuff like this from happening.